Farming practices that make efficient use of renewable (or replaceable) resources and are based upon the fundamental principle of not harming the environment or local ecology. Choosing crops to suit the climate, thus reducing the need for irrigation, is one example.

Compounds consisting of chlorine, fluorine, and carbon. CFCs are found as coolants in refrigerators and air conditioners. CFCs released into the atmosphere are one of the causes of holes in the ozone layer, leading to global warming and other environmental problems. One chlorine atom from a CFC can destroy more than 100,000 ozone molecules. A leaky air conditioner that uses CFCs can destroy millions of ozone molecules.

From the hot arid deserts of the Sahara, through the lush green rainforests of the Amazon, to the ocean depths and bright corals, our natural world is a marvel of different landscapes, materials, colours and textures.

The land, air and seas of our planet are home to the tiniest insects and the largest animals, which make up a rich tapestry of interconnecting and interdependent forces.

The Sun powers Earth’s climate, radiating energy at very short wavelengths, predominately in the visible or near-visible (e.g., ultraviolet) part of the spectrum. Roughly one-third of the solar energy that reaches the top of Earth’s atmosphere is reflected directly back to space. The remaining two-thirds is absorbed by the surface and, to a lesser extent, by the atmosphere. To balance the absorbed incoming energy, the Earth must, on average, radiate the same amount of energy back to space.